The invention relates to lens grinding and polishing apparatus, and, more particularly, to a lens grinding and polishing apparatus for moving the lenses relative to the polishing head in a single plane.
It is generally the practice in the lens grinding and polishing industry to polish a plurality of lenses at one time in a manner whereby the lens is brought to engage a polishing or grinding implement moved relative thereto. Such apparatus generally includes a lens table or stand, which upstands from various mechanical linkages imparting movement thereto relative to the polishing or grinding implement. One such prior art embodiment includes a single, vertically mounted shaft which supports the aforesaid lens table. The lower portion of the shaft is arcuately driven in a circular pattern to move the lens throughout a circular path of a predefined dimensions facilitating the grinding of the total surface area thereof. The drive mechanisms for such prior art devices have often included intricate and complicated drive networks for facilitating the aforesaid multi-directional actuation through multi-axis gimbal mounts. Although gimbal mountings are relatively effective, certain problems coexist therewith.
In the grinding and polishing of relatively smaller lenses of the type used in eyeglasses and the like, the aforesaid gimbal mount, induces a slight angulation to the lens table throughout the lateral movement thereof. The slight angulation in the lens table is transferred to the lens relative to the polishing or grinding head, inducing slight edge aberrations upon the lens and related problems. One such related problem is the "slapping" of the lens against the polishing or grinding implement, oftentimes a tapered arm engaging the lens, which arm is adapted for continuous pressured engagement therewith. Whenever "slapping" occurs, a poorer quality polishing results. The "slapping," however, is inevitable with the slight angulation induced upon the lens through the gimbal mount. The degree of slapping may only be reduced by an increase in length of the table support arm, whereby the magnitude of the angulation deflection is reduced as a trigonometric function thereof.
It would be an advantage therefore, to overcome certain of the problems and inconveniences of prior art apparatus by providing an improved lens polishing and grinding apparatus which would move the lens in about a single plane relative to the polishing or grinding head. The lens-grinding apparatus of the present invention is especially adapted for use in polishing a lens through the movement of a lens support table actuated in a single plane relative to the polishing head. The coplanar actuation is effected through the eccentric drive of lens drive cams supported about orthogonal alignment arms. In this manner the operation of grinding or polishing optical lenses is facilitated without the "slapping" and/or distortion of the lens due to the prior art angulation of the support table.